Flutter、in_app_purchase：显示订阅到期日期或状态的方式

如何解决Flutter、in_app_purchase：显示订阅到期日期或状态的方式

使用 in_app_purchase: ^0.3.5+1 包，我试图验证用户是否在 iOS 上拥有有效订阅。

我可以通过 productID 获得 transactionDate 和 purchaseDetails.productID & purchaseDetails.transactionDate。但我似乎无法获得到期日期或状态。观看他们谈论“状态”的苹果视频堆积如山。如果交易日期知道他们是否取消，我不确定是否有人开始免费试用 3 天，因此没有信心将所有内容都基于此交易日期。

我可以得到 purchaseDetails.verificationData.localVerificationData，它似乎是一个 ANS1 字符串，这可能有更多信息，但我似乎无法对其进行解码。有没有人现在如何为iOS解码？或者知道另一种获取订阅状态的方法？

我尽量不使用诸如 RevenueCat 之类的平台（因为他们会分一杯羹），不过它们似乎提供了这样的功能。

以下是 ASN.1 字符串：

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解决方法

该字符串确实是 ASN.1 数据。您可以在线解码字符串，例如使用 https://lapo.it/asn1js/。解码后的数据包含一些日期字段，所以也许你需要的信息就在那里。您需要一个 ASN.1 架构才能真正了解哪个字段的含义。

为了在你的应用中解码 ASN.1 数据，你需要使用一些 ASN.1 解码库你也可以尝试为 ASN.1 BER（基本编码）编写一个 TLV 解码器（标签长度值）规则），这将帮助您从数据中获取单个字段。这不应该过于复杂来实现。将 ASN.1 BER 数据解码为 TLV 后，您可以进一步仅解码一些对您有用的特定字段。